Regulator



March 13, 1951 H. A. ALEXANDERSON ET AL 2,544,973

REGULATOR Filed Nov. 18, 1944 5 Sheets-Sheet 1 H1B NIR hummm 2.1mm ...o

By Heilig CCNeie,

Hou/am! A Alexcuzderso/L March 13, 1951 H. A. ALExANDERsoN ET AL REGULATOR 5 Sheets-Sheet 2 Filed Nov. 18. 1944 MalCh 13 1951 H. A. ALExANDERsoN ET A1. 2,544,973

REGULATOR 3 Sheets-Sheet 5 Filed Nov. 18, 1944 Patented Mar. 13, 1951 REGULATOR Howard A. Alexanderson, Wood-Ridge, and Henry C. N ette,Rutherford, N. J., assignors to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application November 18, 1944, Serial No. 564,092

Claims.

The present invention relates to improvements f in regulators of the type shown in the copending application Serial No. 551,036, filed August 24, 1944, now Patent No. 2,453,653 patented Nov. 9, 1948, by Howard A. Alexanderson and more particularly to novel means for controlling the air inlet pressure of a supercharged aircraft engine so as to maintain the pressure thereof at selected pressures.

During the operation of so-called water or anti-knock fluid injection systems for suppressing predetonation in internal combustion engines, an increase in the air inlet pressure of the induction system for the engine is permissible and desirable in order that greater engine power may be obtained than when such injection system is not in operation. Therefore, an object of the present invention is to, provide a regulator responsive to operation of such an injection system for effecting a predetermined increase in the air pressure in the induction system during the operation of such a system.

Another object of the invention is to provide a novel regulator arranged to maintain the air inlet of a supercharged aircraft engine at a first preselected pressure value, when such supplemental iiuid injection system is not in operation and said regulator further arranged to maintain such pressure at a second relatively higherL reset pressure when such injection system is in operation together with novel means for varyingsuch selected pressure values within a predetermined range.

Another object of the invention is toprovide novel manually operable means for adjustingthe setting of the regulator, including a Vfirst spring means for setting the datum of the regulator, and second means for adjusting the tension ofvsaid rst spring means including a second spring opposing the biasing force of the first spring.

Another object of the invention is to provide second novel means for adjusting the range of the setting of the normal and reset pressure values of the regulator.

A further object of the invention is to provide a novel regulator for a supercharger.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only, and are not de-l signed as a definition of the limits of the inven' tion, reference being had to the appended claims for this purpose. f

In interpreting the appended claims, where they refer to'a supercharger, they are to be construed as including application of the 'invention to any known type supercharger, however driven, and to any type of throttle controlled engine, and, where the claims are directed to less than all of the elements disclosed, they are intended to cover possible uses of the recited elements in installations which lack the non-recited elements. g

In the drawings, wherein reference numerals refer to like parts throughout 'the several views:

Figure l is a schematic view illustrating the manner in which the regulator may be connected Figure 3 is a sectional view of the operating lever of Figure 2 taken along the lines 3-3 of Figure 2.

Figure 4 is an enlarged interior View of the regulator adjusting mechanism of Figure 1 with the side plate broken away.

Figure 5 is an exploded perspective View of the improved regulator adjusting mechanism. VReferring rst to Figure 1, there is shown `in dotted outline a typical radial aircraft engine I drivingly connected in a conventional manner to a supercharger 2. The supercharger 2 has provided conduits 3 discharging into the cylinder intakes of the engine I. The engine I is alsoV provided with a carburetor indicated generally by numeral 4 operably connected by means of conduit 5 to the inlet of the supercharger 2. A conventional butterfly valve 6 is provided in the conduit 5. The valve 5 has the usual operating lever 'I positioned by a pilots control lever 8 through connecting rod 9. A conduit IIJ connects through an intercooler I I the air inlet of the carburetor i to the outlet of a primary stage supercharger I2. The supercharger I2 may be drivingly connected through a shaft I3 to the aircraft engine I or to any other-suitable driving means. A conduit I4 connects the inlet of the supercharger I2 to the atmosphere through a suitable air inlet member I5.

A conventional butterfly valve I6 having an operating lever Il is provided in the air inlet I4 for the supercharger I2. lThe lever Il is operatively controlled by a regulator I8, as will be hereinafter explained.

As best shown schematically in Figure 1, there is connected to the carburetor 4 a conduit I9 leading from a suitable source of uid fuel for the aircraft engine. There is also provided a conduit 2li for injecting the fuel into the induction system through a nozzle 29A. There is further provided a conduit 2l for injecting into the induction system through nozzle A a supplemental or so-salled anti-knock fluid medium such as water, water-alcohol or other suitable uid well known in the art for suppressing predetonation of the engine I.

The conduit 2l is connected to a suitable metering device shown in dotted outline and indicated generally by the numeral 22. The latter metering device may be of any suitable type known in the art for determining the rate of flow of the supplemental fluid, and, since the herein invention resides in the regulator means rather than in the metering device, the saine has been shown diagrammatically by the outline indicated by numeral 22.

A conduit 23 leads to the metering device 22 from a suitable source of supplemental fluid indicated by numeral 24. In the conduit 23, there is provided a pump indicated by numeral 25 driven by a suitable power means not shown. The pump 25 supplies the fluid medium under pressure to the metering device 22. A valve 26 is provided in the conduit 29 between the pump and metering device 22 for off and on control of the supplemental fluid injection system. The control valve 26 may be of any suitable type, but is shown herein as of an electromagnet controlled type having an electrical control circuit 2l and switch 28 which is preferably mounted within the aircraft cabin for convenient operation by the pilot. Thus the supplemental fluid injection system may be placed in operation by the pilot closing the switch 28 so as to effect the opening of the valve 26. Conversely, the valve 29 may be closed by opening the switch 28. A by-pass conduit 29 and relief valve 3D is provided for recirculating the uid medium from the pump outlet to the pump inlet at such times as the valve 26 is closed and the injection system is not in operation.

A conduit 3l is connected to the conduit 23 betweenv the valve 25 andthe metering device 22. The conduit 3l leads to the regulator I8, so that during operation of the injection system, the regulator i8 is subject to the pressure of the supplemental uid medium under force of the pump 25, as' will be explained hereinafter. It will be readily seen, however, that, when the injection system is in operation, the huid medium `will exert through the conduit 3i a greater pressure under force of the pump 25 than when the injection system is not in operation.

The regulator I8, as best shown in Figures 1 and 2V, includes a casing or housing i8 having end plates il and 42 fastened at opposite ends of the casing S9 by bolts 43 and 44, respectively.

Positioned within the casing i9 and between the end plates 4l and 42 are three flexible walled `cylinders or bellows e5, 45, and 4l. The bellows 45 fastened at one end to a plate 48 connected to the end plate lll by bolts 49. The opposite end of the bellows 45 is fastened about the adjacent ends of bellows 46 and a sealing plate 59 interposed between the opposite ends of the bellows 45 and 46.

A second sealing plate 5| is positioned at the other end of the bellows l5 and has the adjacent ends of bellows 49 and 41 secured about the periphery thereof.

The opposite ends of bellows 41 are secured to the sides of a rigid cup-shaped member 52 having a flanged portion 53 which engages a raised portion 54 projecting from the inner surface of the casing 4D. The open end of the cupshaped member 52 is closed in sealing relation by the end plate 42. Ports 55 open from the interior of the member 52 into the interior of the bellows 4T.

The conduit 3 I, as best shown in Figure 1, connected at one end to the supplemental fluid supply conduit 23, is connected at the opposite end to a nipple B0 mounted in the end plate 42 and opening through a suitable passage, not shown, into the interior of the cup-shaped member 52.

A second conduit TU leads from the carburetor air inlet conduit IB to a nipple 'il mounted in the side of casing 46. The nipple l opens into a suitable passage formed in the wall of the casing 40 and leading into a passage formed in end plate 4|, and the latter passage opens into the interior of bellows 45.

A helical spring 3B is positioned within the bellows l5 and has one end biased against the plate 59, while the opposite end of the spring 89 is held by a plate 3l affixed toa longitudinally adjustable rod S2. The rod 82 is slidably mounted in a sleeve 83 mounted in the end plate 4l and has an end portion 84 projecting through the plate 4I into a chamber 85 provided in a casting 39. The latter casting is formed integral with the end plate 4l. A suitable cap member 8l closes the chamber 85 and suitable mechanism is provided for slidably adjusting the rod 82 as will be explained hereinafter. It will be readily seen, however, that, by slidablj7 adjusting the rod 82 in the end plate 4I, the relative position of the plate 8l may be adjusted longitudinally so as to vary the tension exerted by the spring all.

As shown in Figure 2 the bellows i5 is evacuated and has provided therein a second spring interposed between the end plates 59 and 5l and tending to bias the plate 58 so as to oppose the biasing force exerted on the plate 56 by the spring 89d The plate 5! has provided a novel support including a stem member 9| affixed to the plate 5I and having portions 92 and 93 projecting at opposite sides thereof into the bellows 46 and 41 respectively.

The portion 93 engages one side of the plate 5I, while a tubular member 94 surrounds the portion 92 and is drawn into engaging relation with the other side of the plate 5i by a disk 95 fastened at the free end of the portion 92 by a screw 96. The disk 95 is arranged to move freely within a strap 91 fastened at one end by a rivet member 98 to the plate 50. The strap 91 has a anged portion 99 provided at the other end arranged to engage the disk 95 at the extreme limit of movement of the plate 59 under the lbiasing force of the spring 90. Similarly, the screw 95 will engage the rivet member 9B to limit the movement of the plate 59 in the opposite direction under the biasing force of the spring 80 augmented by the biasing force of the pressure medium introduced int-o the bellows 45 through the conduit 10. Thus, the expansion and contraction of the bellows 45 and 45 may be limited within a safe range, so as to prevent `under extreme pressure conditions the overtravel of a control valve |52 operably connected thereto.

The portion 93 of the stem 92 slides within a collar |08 projecting into the bellows 4l from the 'cuprshaped member 52.7.. A screwthreaded.c1101 '|0| projects from the portion 93 andvhas screw threadedly engaged thereon a nut portion |02 having a flange |03 mountedat one end` thereof. The opposite end of the nut portion |02 is suitably recessed so as to receive part of the portion 93 upon longitudinal adjustment ofthe nut|02 in relation thereto. The flange |03 of the nut |02 is arranged to engage the inner surface ofthe member 52so as to limit the movement of the plate 5| upon expansion of the bellows 41 under the biasing force of a pressure medium, therein, as will be explained,AA Y

Movement of the plate 5| in an opposite direction as upon contracting of the bellows 4`| is limited by the free end |05 of the portion |0| contacting an adjacent end |06 of an adjustable stem H0.

The adjustable stem is screw threadedly engaged in a sleeve portion l l of a stem ||2 having a screw threaded end portion H3. The stem ||2 and sleeve portion lll are rotatably mounted in a sleeve He which projects through the end plate 42. The sleeve H4 has provided at the inner end thereof aiange portion H which engages the inner surface of the end plate 42. Suitable screw/threads H6 are provided on the outer surface of the sleeve ||4 for engagement by a suitable nut which fastens the lsleeve H4 in the end plate 42 at the outer side thereof. A suitable sealing member H0 is positioned between the end plate 42 and the flange ||5 for preventing leakage of a fluid medium.

Provided within the sleeve l I4 is a shoulder |20 arranged to cooperate with shoulder |2| provided on stem |I2 to prevent outward longitudinal movement of the stem ||2 in relation to the sleeve |4. A suitable sealing member i3 is positioned between the shoulders |20 and |2|. A nut |22 is positioned at the outer end of the stem |2 in screw threaded engagement with the;y portion |3 and in contacting relation with the outer end of the sleeve ||4 so as to prevent inward longitudinal movement of the stem |E2 in relation to the sleeve H4. A cleft portion |30 is provided at the end of the stem ||2 while a hexagonal shaped portion |3| is provided on the sleeve H4, as best shown in Figures 1 and 2, for facilitating rotary adjustment of the stem i|2 and sleeve l i4, as will be explained. A cover cap |32 is provided to prevent accidental adjustment of the sleeve |4 and stem 2 and may be screw Y threadedly mounted on the threads H0.

A pin |40 is fixedly mounted in the flange |15 at the inner end of the sleeve |54 and extends longitudinally into a suitable slot 64| formed in the flange |03 of the nut |02 so that the nut |02 may be rotatably connected to the sleeve ||4. Further, a plate |42 is fixedly mounted at the free end of the adjustable stem ||0. The plate |42 has provided a suitable notch |43 in which is engaged the pin |40 so as to prevent relative rotary movement between the stem H0 and sleeve ||4. Y

From the foregoing-it will be readily seen that, by rotating the stem ||2 relative to the sleeve I4 through means of a screwdriver 0r other suitable tool operably engaged in the cleft |30, the stem H0 screw threadedly engaged in the sleeve l will move longitudinally since the same will be secured against rotary movement by the pin |40 carried by the sleeve ||4 which may be held against rotary movement in any convenient manner. Thus, the position of the end |05 of the stem I0 may be adjusted in relation to the end los of the stem ml and accordinglythe return or initial position of the plate 5 l, as shown in Figure 2, may be varied.u Thusnthe range of pressure settings under normal operation through adjustment of the rod 82 may be varied, f

Moreover, upon imparting a rotary movement to the sleeve ||4 in relation to the end plate 42 through means of a wrench or other suitable means operably engaging the hexagonal portion |3I, it will be seen that a corresponding rotary movement will be imparted through the pin |40 to the nut |02 through the ange v|03 and connecting slot |4l. Such rotary movement will cause the nut |02 to move longitudinally on the screw threaded portion |0| of the stem 53, since the stem 03 is xedly mountedion the plate 5| against a rotary movement relative thereto.

k Such longitudinal movement of the Ynut |02 will vary the position of the flange |03 in relation to the inner surface of the cupi-shaped member 52 and thereby provide means for adjusting the second or reset position of the plate 5| and accordingly, throughadjustment of the spring 90, the reset pressure setting of the plate 5 0 for a given position of the rod 82. Through adjustment of sleeve |4, the range of pressuresettings under water injection operating conditions may ton |53 slidably positioned in a cylinder notv be varied.

As shown in Figure 2, there is operably con- Y nected to the plate 5t an arm |50 which extends in rigid fashion eXteriorly from the same.V A link |5| connects the arm |50 to a control valve |52 slidably mounted in a valve cylinder |52A closed by a suitable plug |52B. l ,Y i

There is provided in the casing 40 a servo pisshown, having two ports |55 and |50 on opposite sides of said piston, through which ports fluid is caused to new whenever corresponding spaced covering portions |60 and ll, respectively, of the control valve |52 are not in flow inhibiting relation thereto. I Y

The operating fluid may be oil received from the engine oil supply by way of port |02 formed in a mounting pad |63 as shown in Figure 1.

The oil may be returned from the piston cylinder by way of port 04 or |05 leading into the interior of the casing 40 from'the valve cylinder |52A, as the case may be, whenever a shifting of the control valve |52 from its neutral position causes one of said ports |64 or` |05 to receive oil discharged from the piston cylinder'.y A port |66 formed in the mounting pad |63 carries the discharged oil from the interior of the casing 4@ to a return conduit leading to the engine oil sump.

As best shown in Figure 1, a piston |53 is operably connected at its free end by a link 54 to the operating lever of the valve l5 for controlling the air inlet to the supercharger I2.,

Referring now to the novel adjustable rod 82 the mechanism for adjusting the same includes, as shown in Figures 2, 3, 4, and 5, an anti-friction rollerV bearing 200 rotatably mounted by suitable ball bearings on a tubular member 205 projecting from an arm 202 fastened to a shaft 203. The member 20| is positionedin eccentric relation to the shaft 203. which is rotatably mounted in an eccentric sleeve 204 positioned in the casting 85 at right anglesto the slidable rod 82.

The yanti-friction roller bearing 200 is rotatably mounted on the tubular member 20| and held in the tubular member 20|.

assi-,cvs

bearing 2e!) in a oounterclockwi'se direction about w one end of the shaft 293 and into contacting relation with the' end S4 of the rod 82. The spring 2li! thus opposes the biasing' force of the spring 80.

The opposite end of the shaft 203 projects from the casting 86 and has provided at the latter end thereof a squared portion 2|`5 and a screw threaded portion 2 I6.

An arm 2|8 is fastened to the shaft by-means of securing members 2|9 and 228. The member 2|9 has a squared opening 22| corresponding to the squared portion 2|5 and may be locked thereon. The member 2|!! has suitable sci-ration 222 arranged to engage corresponding serrations 225 surrounding an opening 22S formed in the free end of the arm 2|8. The screw threaded portion 216 of the shaft projectsv through the opening 22| and 226 and the serrations 222 and 225 are locked in engaging relation through means of the nut 225 screw threadedly engaged on the screw threaded portion 2 I@ at the opposite side of the arm 2| 8 from the serraticns 225.

It will thus be seen that movement of the arm 2 I8 will impart a corresponding movement to the shaft 263 so as to cause the anti-friction roller bearing S to adjust through rod 52 to the spring B. Movement of the arm 2 [B in a direction for increasing the biasing force exerted by the spring 8B will be augmented by the biasing force exerted by the spring 2|!! and thus adjustment may be effected with a minimum force.

The eccentric sleeve 204 mounted within the casting 85 has provided a flanged portion 23B in which is formed an arcuate slot 23|. There is provided in the arcuate slot 23| a fastening screw 235 screw threadedly engaged in the casting 8E. In order to eie'c't the proper adjustment of the shaft 253 and thus the roller 200 in relation to the rod 82, the ilange 230 may be rotated relative to the casting 86 and fastened in a desired position by means of the screw 235. Y

As shown in Figure 2, there projects into the chamber 85, a limit screw 24|) which is screw threadedly engaged in the casting 86 and is locked in position by a lock nut 24|. The screw 240 has a cleft portion 242 provided at the outer end thereof for the' ready adjustment of the screw 240.

The free end of the arm 2|8 is operably connected by a rod 250 tothe arm 'l of the throttle valve E and operably connected by a rod 9 to the pilots control lever 8. Through the latter arrangement it will be readily seen that as the throttle valve 6 is moved in a closing direction the 'arm 2li! will be moved in a counterclockwise direction, which as shown in Figure 4, will cause movement of the anti-friction roller bearing 255 in a direction for increasing the tension of the spring B0 and thereby decrease the setting or datum of the bellows 45 and accord*- ingly the value of the pressure required to hold the valve |52 in a neutral position.

Thus as the throttle valve 6 is opened, an increase in the datum of the boost and the pressure provided by the supercharger I2 will result 8 while a decrease in the opening of die tai-ortie 5 will eiect an opposite result Through this novel arrangement surging between the nrst and second stage superchargers may be effectively eliminated.

In the adjustment of the regulator I8 for op'- eratio'nv, the 'stein ||2 is rst adjusted so 'as to position the stem 93 and plate 5| in relation to the spring ec in such a manner that a shifting or the plate' 5l to a second or reset position will be effected by the supplemental iuid carried b-"y conduit' 3| at a pressure indicative f opera'- ton of the supplemental Huid injection system and the' range of pressure adjustment readily determined for nOl-lal pltih.

Second, the sleeve ||4 may then be adjusted 'so as to position the ilange |03 of the nut |02 in a vmanner so as to limit the adjustment of the plate 5| during the operation of the supplemental fluid injection system to a position which will eiect a predetermined high pressure setting range for the induction system. Thus, in the latter reset position, through the resulting adjustment of the spring 90, the bellows 45 and 46 forming a pressure boost control will cause the plate 50 to assume a neutral position in relation to the control valve |52 when the carburetor air inlet pressure acting within the bellows 45 is' at the' predetermined increased pressure value set by adjustment of the lever 2| 8 during operation of the supplemental fluid injection system.

In the operation of the regulator I8, it will be seen that, during normal operation, an increase in the pressure at the air inlet to the carburetor above the value set by the position of the lever 2 |8 will cause the bellows 45 to shift the plate 50 to the left, shifting the control valve |52 and actuating the servo piston |53 of Figure 1 to the right, tending to close the valve I6 to the supercharg'er inlet and thereby decreasing the pressure in the carburetor air inlet I0 until the valve |5i is returned to a neutral position. A decrease in the carburetor inlet pressure below such set value will eiect an opposite adjustment of the valve I6 and increase the pressure at the carburetor air inlet. Thus, while the altitude of the aircraft or other operating conditions of the aircraft may vary effecting the induction pressure, the regulator i8 will tend to readjust the valve |5 so as to maintain such pressure at a substantially constant value;

pon initiating the operation of the supplemental fluid injection system by opening the valve 26, a uid medium will be supplied the conduit 23 under pressure of the pump 25, whereupon the fluid pressure supplied the regulator I3 through the conduit 3| will be' increased, effecting an expansion of the bellows 41 and the shifting of the plate 5| from theposition shown in Figure 2 to a second position to the right, as determined by the adjustment of the flange |03, and' thereby changing the datum or setting of the boost control, bellows 45 and 46. Thus, such an adjustment of the plate 5| will cause a corresponding adjustment through the spring of the plate 50 and valve |52, causing the piston |53 to be adjusted to left and opening the valve I6 until the pressure within the carburetor air inlet conduit |l has been increased to such a value as to bias the plate 50 to the left so' as to return the valve |5| to a neutral position. The bellows 45 and 46 will then tend to maintain the pressure at the latter reset value. The said increased boost pressure will permit greater engine power to be obtained during operation of the supplemental uid injection system than would begotherwise possible.

However, upon the operation of the supplemental Huid injection system being discontinued, the pressure supplied the bellows 41 through the conduit 3| will be decreased, whereupon the spring 90 will return the Yplate 5l to the position, shown in the Figure 2, and the pressure setting or datum of the boost control 45 and 46 will once again resume the normal value for the first position.

It will be noted moreover that through operation of the lever 2 I8 interconnected to the throttle control lever 8, the pressure setting of the boost control may be readily varied during normal operation and during the operation of the supplemental fluid injection system within ranges determined by the adjustment of the stem H2 and sleeve H4 respectively. Moreover in view of the interconnection between the throttle valve Ei and the lever 2|8 an increase in the setting of the boost will be jointly effected with the opening of the throttle valve 6, while a decrease in the setting of the boost will be jointly effected with the closing of the throttle valve 6 so as to avoid objectionable surging in the air ow between the rst and second stage superchargers.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A regulator for an engine of an aircraft comprising, in combination, a nrst member responsive to a first condition, a second member responsive to a second condition, spring biasing means interposed between said rst and second members for biasing said members in opposite directions, control means operated by said iirst member in response to said rst condition, said second member adjusting the biasing force of said f spring means in response to said second condition for varying the datum of said iirst member, and other means for adjusting the datum of said rst member, said other means including second spring means for counteracting the biasing force of' said first mentioned spring means, roller bearing means adjustably positioned for varying the force exerted by said second spring means and means to connect said roller bearing means for operation from a cabin of the aircraft.

2. A regulator comprising, in combination, a rst bellows responsive to a first condition, a second bellows responsive to a second condition, spring biasing means interposed between said rst and second bello-ws for biasing said bellows in opposite directions, control means operated by said first bellows in response to said first condition, said second bellows adjusting the biasing force of said spring means in response tosaid second condition for varying the datum of said first bellows, and other means for adjusting the datum of said rst bellows, said other means including spring means for counteracting the biasing force of said rst mentioned springmeans, roller bearing means adjustably positioned for varying the force exerted by said last mentioned spring means, and a third spring means acting upon said roller bearing means in a direction opposing the biasing force of said last mentioned spring means.

means interposed between said rst and second bellows for biasing said bellows in opposite directions, control means operated by said rst bellows in response to said rst condition, said second bellows adjusting the biasing force of said spring means in response to said second condition for varying the datum of said rst bellows, other means for adjusting the datum of said first bellows7 said other means including spring means for counteracting the biasing force of said first mentioned spring means, roller bearing means adjustably positioned for varying the force eX- erted by said last mentioned spring means, means to connect said roller bearing means for operation from a cabin of the aircraft, and means for adjusting the operating range of said datum changing means.

4. A regulator comprising, in combination, `a rst bellows responsivefto a first condition, a second bellows responsive to a second condition, spring biasing means interposed between Ysaid rst and second bellows for biasing said bellows in opposite directions, control means operated by said first bellows in response to said first condition, said second bellows adjusting the biasing force of said spring means in response to said second condition for varying the datum of said first bellows, and other means for adjusting the datum of said rst bellows, said other means including spring means for counteracting the biasing force of said first mentioned spring means, roller bearing means adjustably positioned for varying the force exerted by said last mentioned spring means, means to connect said roller bearing means for operation from a cabin of the aircraft, rst means for adjusting the operating range of said other datum changing means and effective during inoperation of said second bellows, and second means for adjusting the operating range of said other datum changing means and effective upon operation of said second bellows in response to said second condition.

5. A regulator comprising, in combination, a first member responsive to a first condition, a

second member responsive to a second condition, Y

spring biasing means interposed between said first and second members for biasing said members in opposite directions, control means operated by said rst member in response to said first condition, said second Vmember adjusting the biasing force of said spring means in response to said second condition for varying the datum of said first member, manually operable means for changing the datum of said rst member during operation and inoperation of said second member, and means for adjusting the operating range o' said datum changing means during the operation and inoperation of said second member.

6. Means for adjusting biasing force of a spring element, comprising, in combination, a casting providing a housing for said means, a longitudinally adjustable rod slidably mounted in said casting and bearing at one end upon said spring element for adjusting the biasing force' thereof, a shaft rotatably supported in said casting, said shaft having one end positioned within the casting and another outer end projecting from said casting, a member projecting from the one end of said shaft and positioned in eccentric relation to said shaft, an annular shaped roller member rotatably mounted on said projecting member and `contacting at its peripheral edge another end of said rod, spring means biasing said projecting member and thereby said roller member in a direction opposing the biasing force of said spring element, and manually operable means connected at the outer end of the shaft for adjustably positioning said roller member about the axis of rotation of said shaft for the adjustment of said spring element.

7. Means for adjusting biasing force of a spring element, comprising, in combination, a casting providing a housing for said means, a longitudinally adjustable rod slidably mounted in said casting and supporting at one end said spring element, a shaft rotatably supported in said casting, said shaft having one end positioned within the casting and another outer end projecting from said casting, a tubular member projecting from the one end of said shaft and positioned in eccentricrelation to said shaft, an annular shaped roller member, ball bearings rotatably mounting said member on said projecting member, said roller member contacting at its peripheral edge another end of said rod, a helical spring positioned about said shaft, one end of said spring secured by said casting and an opposite end of said spring positioned in said projecting tubular member so as to bias the projecting tubular member kabout the axis of rotation of said shaft and said annular roller member in a direction opposing the biasing force of said spring element, and a control arm aflixed to the outer end of the shaft for rotation of said shaft so as to effect adjustment of the biasing force of the spring element.

8. For use in a pressure regulator including a fluid pressure responsive member, and adjustable spring means for varying the datum of said pressure responsive member; the combination comprising a longitudinally adjustable rod adapted to be `operably connected at one end to said spring means, a roller member operably contacting the other end of said rod, a shaft, a member projecting vfrom one end of said shaft and positioned in eccentric relation to said shaft, ball bearings rotatably mounting said roller member concentrically on said projecting member, a second spring means positioned about said shaft and biasing said roller member in a direction opposing the biasing force of said rst mentioned spring means, manually operable means for adjustably positioning said roller member about the axis of rotation of said shaft for adjusting said first mentioned spring.; means.

9. For use in a pressure regulator including a fluid pressure responsive member, and an adjustable spring for varying the datum of said pressure responsive member; the combination comprising a roller member, means adapted to operably connect said roller member to said pressure responsive member through said spring, a shaft, a Vmember projecting from one end of said shaft and positioned in eccentric relation to said shaft, said roller member rotatably mounted on said projecting member and adjustably positioned about the axis of rotation of said shaft for adjusting the spring and thereby the datum of said pressure responsive member, another spring biasing said roller member in adirection opposing the biasing force `of said fir-st mentioned spring, and manually operable means for adjustably positioning said shaft and thereby the roller member relative to said first mentioned spring.

10. For use in a pressure regulator including a fluid pressure responsive member, and an adjustable spring for varying the datum of said pressure responsive member; the combination comprising a roller member, means adapted to operably connect said roller member to said pressure responsive member through said spring, a shaft, a tubular member projecting from one end of said shaft and positioned in eccentric relation to said shaft, a helical spring positioned about said shaft, one end of said helical spring fixedly mounted and the opposite end of said helical spring positioned in said tubular member so as to bias said roller member in a direction opposing the biasing force of said first mentioned spring, said roller member rotatably mounted on said tubular member and adjustably positioned about the axis of rotation of said shaft under the biasing force of said helical spring to adjust the datum of said pressure responsive member.

HOWARD A. ALEXANDERSON. HENRY C. NETTE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,324,083 Tolmin Dec. 9, 1919 1,579,536 Hodgson Apr. 6, 1926 1,841,337 Roessler Jan. 12, 1932 2,098,914 Gorrie Nov. 9, 1937 2,282,529 Pierce May 12, 1942 2,323,204 Cross J'une 29, 1943 FOREIGN PATENTS Number Country Date 475,389 Great Britain Nov. 18, 1937 

